#include <iostream>
#include <vector>
using namespace std;

class Solution {
public:
    int tribonacci(int n) {
        vector<int> dp(38);
        dp[0] = 0;
        dp[1] = dp[2] = 1;
        for (int i = 3; i < n + 1; ++i) dp[i] = dp[i - 1] + dp[i - 2] + dp[i - 3];
        return dp[n];

    }
};

int main()
{
	return 0;
}